The present invention relates to the field of ophthalmology. More particularly, this invention relates to the treatment of inflamed ocular tissue.
Many compounds classified as glucocorticoids, such as dexamethasone and prednisolone, are very effective in the treatment of inflamed tissues, but in certain patients, these compounds cause elevations in intraocular pressure. Patients who experience elevations in intraocular pressure when treated with glucocorticoids are generally referred to as "steroid responders". The elevations in intraocular pressure are of particular concern in patients who are already suffering from elevated intraocular pressures, such as glaucoma patients. Moreover, there is always a risk that the use of glucocorticoids in patients who have normal intraocular pressures will cause elevations in pressure that result in damage to ocular tissue. Since therapy with glucocorticoids is frequently long term (i.e., several days or more), there is potential for significant damage to ocular tissue as a result of prolonged elevations in intraocular pressure attributable to that therapy.
The following articles may be referred to for further background information concerning the well recognized association between ophthalmic glucocorticoid therapy and elevations in intraocular pressure: Kitazawa, "Increased Intraocular Pressure Induced by Corticosteroids", American Journal of Ophthalmology, Vol. 82, pages 492-495 (1976); Cantrill et al., "Comparison of In Vitro Potentcy of Corticosteroids with Ability to Raise Intraocular Pressure", American Journal of Ophthalmology, Vol. 79, pages 1012-1016 (1975); and Mindel et al., "Comparative Ocular Pressure Elevation by Medrysone, Fluorometholone, and Dexamethasone Phosphate", Archives of Ophthalmology, Vol. 98, pages 1577-1578 (1980).
One approach to solving the foregoing problems has been to search for compounds which are capable of alleviating ophthalmic inflammation without elevating intraocular pressure. The inventions described in U.S. Pat. No. 4,686,214 and in copending U.S. patent application Ser. No. 864,610, filed May 19, 1986, represent two examples of this approach. Notwithstanding the success of the therapies described in the above-cited patent and patent application, there continues to be a need for still further improvements in the treatment of ophthalmic inflammation, such as an improvement which would allow potent glucocorticoids to be utilized to treat inflamed ocular tissue without fear of elevating intraocular pressure.